Quad copter is an aerial vehicle which is operated to fly independently. There are several advantages to quad copters over comparably-scaled helicopters. First, quad rotors do not require mechanical linkages to vary the rotor blade pitch angle as they spin. This simplifies the design and maintenance of the vehicle. Second, the use of four rotors allows each individual rotor to have a smaller diameter than the equivalent helicopter rotor, allowing them to possess less kinetic energy during flight. This reduces the damage caused should the rotors hit anything. For small-scale UAV's, this makes the vehicles safer for close interaction. Some small-scale quad -copters have frames that enclose the rotors, permitting flights through more challenging environments, with lower risk of damaging the vehicle or its surroundings. The prototype has four arms made of light weight fiber frame to which four motors can be assembled. These motors are controlled by means of electronic speed controllers (ESC).These ESC's are connected to the pins of control board. The signal from microcontroller goes to ESC's which in turn control the speed of motor. In this design we are using four brushless motors which is able to make the prototype fly and to change its direction. The power distribution in this system is done by a high capacity Li-Po battery giving adequate power supply.
1.2 Problem Definition
During natural disasters like earthquake, landslides, tsunami, etc, a lot of people die and it gets difficult to find the people who need help at that time. The rescue for them takes a lot of time because it becomes difficult to locate these people. The ultimate goal of our project is to create a bird's eye view of the affected area which can be processed and stored for helping the people to get rescued. So it's better to send a robot instead of sending a person for searching purpose during this situation. Now a days this technology can be used for search and rescue, fire fighting, law enforcement, military, research, and news reporting by being able to deploy aerial correspondence much faster than conventional helicopters.
1.3 Objectives
' Design and build a chassis
' Design and build a power distribution system
' To design Quad copter that can control wireless base on remote control.
' To equip Quad copter with stereo camera to display video.
' To test the performance of designed Quad copter.
1.4 Quad copter Technology
After deciding to create the Quad copter, we had to decide what electronics to use and which sensors we would incorporate into it. After a lot of research on the web, we found a couple forums that discussed open source electronic and software components suitable for making a Quad copter. Also, very basic but highly customizable Quad copter bodies were available that were suitable for us to use to create our baseline system. The DIY drone's forum provided good information on what was being done in the amateur drone community and provided important information on what would be possible for us to use for our project. Motivated by the UAV forge challenge, we believed that the Quad copter would be a good design starting point since it could lift off vertically, travel some distance to a specific location, record video of an object, hover if necessary, and return home upon completion. This scenario led us to the conclusion that we would need sensors including gyroscope, accelerometer, compass, GPS, and a battery monitor. We would also need payload components including a camera and a telemetry system to send imagery back to the liftoff site. Furthermore, we would need a control mechanism that would allow flight beyond the line of sight since that was also a requirement. We thought of two approaches for control beyond the line of sight. One was to use the camera and video to allow us to view the flight path from the Quad copter point of view while guiding it with an RC controller. Second, a more ambitious approach would be to use onboard GPS and guidance and a waypoint system to send commands to the Quad copter via the telemetry link which the Quad copter would execute autonomously. We were unable to achieve the second goal in the allotted time, but we continue to make strides towards completing it. In the beginning of the design process, we believed that it would be possible to perform most of the maneuvers and tasks required by the UAV forge challenge but we had no idea if the components we would be able to assemble would meet the performance requirements. We also had to realistically scope our project given a very small budget, a small team, and a limited amount of time to complete.
The block diagram consists of both transmitter and receiver.
From the diagram, we can see that the power is supplied to each of the blocks of the transmitter. The input through joystick is fed to the microcontroller through controlling unit. The signal from the microcontroller is passed through 4 channel RF transmitter to the drone or receiver. An RF Module (Radio Frequency Module) is a usually small electronic circuit used to transmit and/or receive radio signals on one of a number of carrier frequencies. RF Modules are widely used in electronic design owing to the difficulty of designing radio circuitry. Good electronic radio design is notoriously complex because of the sensitivity of radio circuits and the accuracy of components and layouts required achieving operation on a specific frequency.
The signal from the transmitter is received by 4 channel RF receivers and is fed to the microcontroller and using this signal the motors can be turned ON or OFF. ESC controls the speed of the motor depending on receiving input gyro. The ESC as used in radio controlled craft performs two primary functions. The first is to act as a Battery Elimination Circuit (BEC) allowing both the motors and the receiver to be powered by a single battery. The second (and primary) function is to take the receiver's and/or flight controller's signals and apply the right current to the motors.
Each BLDC motor needs an ESC .ESC Regulates power to the motor according to the input throttle level. It also provides +5V power for the flight electronics.ESC is built on 16 bit Microcontroller (ARM) & has an array of MOSFET to drive BLDC motor. The Firmware of ESC is factory programmed
A gyroscope is defined as a rigid rotating object, symmetric about one axis. Generations of children, back at least to Greek antiquity, have found fascination in the behavior of tops, to give the gyroscope its common name. A number of eminent physicists have also found the complex behavior of spinning objects a matter of interest and a fit subject for detailed analysis.
Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors which are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor (AC, alternating current, does not imply a sinusoidal waveform but rather a bi-directional current with no restriction on waveform); additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).including; hands-free calling, multimedia centre, a navigation system and a range of applications which offer features required by the user. These are just some examples, for an open-source expandable system (whereby the framework can be extended and applications can be developed for it). The system can include features such as a reverse camera and other options which can be further developed.
Chapter3: HARDWARE OVERVIEW
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As the name implies, BLDC (Brushless DC) motors do not use brushes for commutation. They are electronically commutated & the advantages are:
Better speed vs. torque characteristics, High efficiency with Noiseless operation & very high speed range with longer life.
You need an Electronic Speed Controller control the motor. As there are no brushes to wear out the life of BLDC motor is much longer. There is no sparking and much less electrical noise.
The only disadvantage of a brushless motor is its higher initial cost.
Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors which are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor (AC, alternating current, does not imply a sinusoidal waveform but rather a bi-directional current with no restriction on waveform); additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).
The motor part of a brushless motor is often a permanent magnet synchronous motor, but can also be a switched reluctance motor, or induction motor.
Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors which are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor (AC, alternating current, does not imply a sinusoidal waveform but rather a bi-directional current with no restriction on waveform); additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).
The motor part of a brushless motor is often a permanent magnet synchronous motor, but can also be a switched reluctance motor, or induction motor.
Brushless motors may be described as stepper motors; however, the term stepper motor tends to be used for motors that are designed specifically to be operated in a mode where they are frequently stopped with the rotor in a defined angular position.
The term out runner refers to a type of brushless motor primarily used in electrically propelled, radio-controlled model aircraft.
This type of motor spins its outer shell around its windings, much like motors found in ordinary CD-ROM computer drives. In fact, CD-ROM motors are frequently rewound into brushless out runner motors for small park flyer aircraft. Parts to aid in converting CD-ROM motors to aircraft use are commercially available.
The stationary (stator) windings of an out runner motor are excited by conventional DC brushless motor controllers. A direct current (switched on and off at high frequency for voltage modulation) is typically passed through three or more non-adjacent windings together, and the group so energized is alternated electronically based upon rotor position feedback. The number of permanent magnets in the rotor does not match the number of stator poles, however. The difference between the number of magnet poles and the number of stator poles provides an effect that can be understood as similar to planetary gearing. The number of magnet poles divided by 2 gives the ratio of magnetic field rotation speed to motor rotation speed. Consequently the advance of the electromagnetic impulse around the motor axis proceeds much faster than the rotor turns. With more magnet poles the maximum torque is increased, while the speed of rotor advance is decreased in proportion to the ratio of magnet poles to stator poles.
Specification of Brushless Motor:
' RPM/V: 930 RMP/V
' Input Voltage: 7.4~11.1V
' No-load Current: 0.4A
' Load Current: 12A
' Shaft Diameter: 3mm / 0.12in
' Cable Length: 60mm / 2.4in
' Dimensions: 38 x 30 mm / 1.5 x 1.2in (L x Dia.)
3.2 Gyroscope Theory
A gyroscope is defined as a rigid rotating object, symmetric about one axis. Generations of children, back at least to Greek antiquity, have found fascination in the behavior of tops, to give the gyroscope its common name. A number of eminent physicists have also found the complex behavior of spinning objects a matter of interest and a fit subject for detailed analysis.
More recently, very carefully engineered gyroscopes were used for navigation because the axis of spin points in a nearly fixed direction when external torques are small. This makes the gyroscope a good replacement for a magnetic compass, particularly in regions where magnetic compasses are unreliable. As with any mechanical system, the motion of a gyroscope can be understood Completely by a systematic to all the